You come at the king, you best not miss. Last week, an attempt to maliciously derail the record-setting rollout of Black Panther – Marvel’s upcoming blockbuster spotlighting the lithe warrior-monarch T’Challa (Chadwick Boseman) – was itself promptly derailed. A scurrilous Facebook event page, whose stated purpose was to “give Black Panther a rotten audience score on Rotten Tomatoes” purported to be a grassroots protest against Disney and its “treatment of franchises and its fanboys”. Amid garbled claims that the corporation that owns Marvel had somehow paid off critics to trash the recent crop of superhero movies from their longstanding rival DC, the page organisers encouraged the use of hashtags like #DownWithDisney and #DCOverMarvel as social media rallying points.

For some commentators, posting a negative rating was a chance to complain about Star Wars becoming too progressive

Plotting to scuttle a film’s Rotten Tomatoes audience score sight unseen seems, at best, underhanded. But the fact this attack was aimed at the most high-profile movie ever to feature a predominantly black cast felt racist. Facebook quickly deleted the event on the grounds that it “violated the company’s community standards”. Rotten Tomatoes, the longstanding film reviews aggregation site that dishes out “fresh” or “rotten” ratings to new releases, responded in even stronger terms: “While we respect our fans’ diverse opinions, we do not condone hate speech.”

In an era when culture wars are predominantly fought on social media, this sort of down-voting can seem like an effective guerrilla tactic. Clicking on an angry red face or selecting zero stars is even easier than adding your name to an online petition, and such basic actions can often be automated. The pre-emptive thumbs-down pile-on that accompanied the female-led Ghostbusters in 2016 – one of the most high-profile instances of the toxic impulse to prejudge art that doesn’t fit in with some preconceived notion of what a franchise should be – means that it still holds the queasy distinction of being the most disliked film trailer on YouTube.

When YouTube launched in 2005, Rotten Tomatoes had already been operational for seven years. But recently the site has become a more fractious battleground, where the professional critical consensus – a film’s final Tomatometer score is determined by assessing reviews from a pool of vetted critics – meets public opinion in the form of crowdsourced audience reactions.

The Greatest Showman, starring Hugh Jackman, was considered rotten by critics, while its audience score was much healthier. Photograph: Niko Tavernise/AP

Perhaps Rotten Tomatoes was so quick to respond to the Black Panther controversy because of the divisive response to another high-profile Disney property. The Last Jedi was officially certified fresh after scoring 91% among critics, a stark contrast to the 48% average score it received from 180,000 audience reactions. For some of these commentators, posting a negative rating was a chance to complain about their favourite franchise becoming too progressive, too feminised or too interested in presenting diversity. (Others just didn’t like the jokes.) The #DownWithDisney agitators suggested they had successfully manipulated The Last Jedi’s audience score using bots, a claim denied by Rotten Tomatoes.

There are examples of similar Rotten Tomatoes score discrepancies with no conspiracy theories swirling around them. The recent PT Barnum musical The Greatest Showman, a big-top passion project from Hugh Jackman, was considered rotten by critics, with a 55% rating on the Tomatometer, while its audience score is a much healthier 91% (from around 18,000 reviews), which would seem to chime with its remarkable ongoing box-office run. There are no claims that a rabid group of diehard Wolverine fans has been artificially inflating The Greatest Showman’s audience score to help their hero.

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The Last Jedi has also made bucketloads of cash, so do these Rotten Tomatoes scores really matter? Last year, the site found itself being blamed by Hollywood executives for the failure of would-be blockbusters Baywatch and The Mummy during a particularly lacklustre summer. (Just a few months later, those claims were being discredited.) More recently, clever marketers have worked out ways to weave an impressive Tomatometer showing seamlessly into a marketing campaign. Greta Gerwig’s coming-of-age tale Lady Bird has been nominated for multiple Oscars and one key thread of that successful awards narrative was that it was Rotten Tomatoes’ new top-rated movie, beating Toy Story 2’s record for consecutive positive reviews. (Lady Bird has since been bested by Paddington 2.)

Even if its splodgy icons of plump juicy veg and snot-green splats can seem rather reductive, Rotten Tomatoes has evolved into a valuable platform for dialogue between cultural gatekeepers and impassioned fans. That’s why keeping it clear of hate speech can only be a good thing.